VIM: Why is this function hanging VIM? - debugging

Question

I have added the following fine function to my status bar to show which function is currently being edited in C-derived languages:
set statusline+=%{WhatFunctionAreWeIn()}
fun WhatFunctionAreWeIn()
let strList = ["while", "foreach", "ifelse", "if else", "for", "if", "else", "try", "catch", "case"]
let foundcontrol = 1
let pos=getpos(".") " This saves the cursor position
let view=winsaveview() " This saves the window view
while (foundcontrol)
let foundcontrol = 0
" Go to the character before the last open {
normal [{
call search('\S','bW')
" If the character is a ) then go to the character
" preceding the () section
let tempchar = getline(".")[col(".") - 1]
if (match(tempchar, ")") >=0 )
normal %
call search('\S','bW')
endif
let tempstring = getline(".")
for item in strList
if( match(tempstring,item) >= 0 )
let foundcontrol = 1
break
endif
endfor
if(foundcontrol == 0)
call cursor(pos)
call winrestview(view)
return tempstring
endif
endwhile
call cursor(pos)
call winrestview(view)
return tempstring
endfun
However, after a few minutes VIM hangs. Disabling the function prevents the hang, so I feel confident that this function is to blame. Is there anything in there that might hang VIM? Is there a better way to accomplish the task of showing the currently-edited function in the status bar?
Thanks.

Answer 1

The issue is that your strategy for determining whether to keep moving to surrounding braces is too aggressive:
Suppose your cursor is on the f in a preprocessor directive #endif between two functions.
Since you're between two functions, there is no unmatched { for [{ to jump to, so the cursor doesn't move.
Your match() against strList hits the if in #endif, causing the loop to continue.
The loop never exits.
I suspect a ctags-based approach, like #Gowtham suggests, will work better, even if it requires some customization.